Why isn't Ubuntu good enough for US classrooms?

Have you used Ubuntu 10.04? It’s my desktop and server platform of choice for basically everything I do. As far as I’m concerned, it has only two weaknesses:

1. It can’t run Office 2010 (the folks at WineHQ are working on this, but it takes a while and it remains to be seen just how well it will run outside of its native environment)

2. It can’t run Adobe CS5.

That’s it. In every other respect, it works wonderfully. It boots quickly, it’s stable, it’s backed by a giant user community whose help and support match the price of the OS, and it can be easily customized to work as the most basic of web servers, a simple Internet kiosk, a free refresh for aging desktops, a high-end media server, a productivity workstation, and everything in between. It can be a terminal server, a high-performance cluster, and a virtualization platform. Huge volumes of software are only a few clicks away. All for free.